thread_return_t CALLING_CONVENTION benchmark_lfds611_freelist_thread_pop_and_push( void *freelist_benchmark )
{
struct lfds611_freelist_benchmark
*fb;
struct lfds611_freelist_element
*fe;
time_t
start_time;
assert( freelist_benchmark != NULL );
fb = (struct lfds611_freelist_benchmark *) freelist_benchmark;
time( &start_time );
while( time(NULL) < start_time + 10 ) {
lfds611_freelist_pop( fb->fs, &fe );
lfds611_freelist_push( fb->fs, fe );
fb->operation_count += 2;
}
return( (thread_return_t) EXIT_SUCCESS );
}
struct lfds611_freelist_element *lfds611_ringbuffer_get_write_element( struct lfds611_ringbuffer_state *rs, struct lfds611_freelist_element **fe, int *overwrite_flag )
{
assert( rs != NULL );
assert( fe != NULL );
// TRD : overwrite_flag can be NULL
/* TRD : we try to obtain an element from the lfds611_freelist
if we can, we populate it and add it to the lfds611_queue
if we cannot, then the lfds611_ringbuffer is full
so instead we grab the current read element and
use that instead
dequeue may fail since the lfds611_queue may be emptied
during our dequeue attempt
so what we actually do here is a loop, attempting
the lfds611_freelist and if it fails then a dequeue, until
we obtain an element
once we have an element, we lfds611_queue it
you may be wondering why this operation is in a loop
remember - these operations are lock-free; anything
can happen in between
so for example the pop could fail because the lfds611_freelist
is empty; but by the time we go to get an element from
the lfds611_queue, the whole lfds611_queue has been emptied back into
the lfds611_freelist!
if overwrite_flag is provided, we set it to 0 if we
obtained a new element from the lfds611_freelist, 1 if we
stole an element from the lfds611_queue
*/
do
{
if( overwrite_flag != NULL )
*overwrite_flag = 0;
lfds611_freelist_pop( rs->fs, fe );
if( *fe == NULL )
{
lfds611_ringbuffer_get_read_element( rs, fe );
if( overwrite_flag != NULL and *fe != NULL )
*overwrite_flag = 1;
}
}
while( *fe == NULL );
return( *fe );
}
void lfds611_stack_internal_new_element_from_freelist( struct lfds611_stack_state *ss, struct lfds611_stack_element *se[LFDS611_STACK_PAC_SIZE], void *user_data )
{
struct lfds611_freelist_element
*fe;
assert( ss != NULL );
assert( se != NULL );
// TRD : user_data can be any value in its range
lfds611_freelist_pop( ss->fs, &fe );
if( fe == NULL )
se[LFDS611_STACK_POINTER] = NULL;
if( fe != NULL )
lfds611_stack_internal_init_element( ss, se, fe, user_data );
return;
}